Bayard H. Brattstrom of California State University, Fullerton's Department of Biology claims that there are no subspecies of the coast horned lizard.

Studying specimens from the San Diego Natural History Museum, he could not match a given lizard to a particular claimed subspecies — for example, Phrynosoma coronatum blainvillii or Phrynosoma coronatum frontale — based on characteristics the subspecies were said to have, such as size of frontal scales.

However, in 2021 Gunther Köhler again reclassified blainvillii and cerroense as subspecies of P. coronatum, although the Reptile Database has not followed this taxonomic change.

[6][7] The coast horned lizard appears rough and spiky but is actually smooth-skinned, although it has sharp spikes along its sides, back and head.

There are four different variations of coast horned lizards that share several similarities but vary in morphological characters.